Invasive Species — Didemnum Tunicate (Didemnum vexillum)
Get Involved

  • Become a Citizen Scientist! Contact ADF&G to find out how you can help monitor for invasive species in your area.
  • Guide to some common native and nonnative fouling invertebrates of Alaska:
  • Be observant. Report any animal or plant you think is unusual and may be a nonnative pest. Note the location of the organism either on a map or with a GPS, take a photo, and immediately call the Alaska Department of Fish and Game invasive species hotline: 1-877-INVASIV or e-mail
  • Avoid infested waters- Avoid Whiting Harbor near Sitka. If you have visited an area known to be infested with an aquatic pest, inspect anchors, ropes and chains before leaving the area and dispose of any unusual plants or animals in a sealed container in a trash can. Let lines and anchors dry completely, rinse or soak thoroughly with fresh water for several minutes.
  • Keep your vessel hull free of fouling. Don’t let pests hitchhike to a new location on your boat. Maintain antifouling treatments to your vessel hull, as appropriate. Do not conduct any hull scraping in the water. Use a dry dock or other facility where the fouling material can be collected and disposed of in an upland area or landfill.
  • Don’t move contaminated gear. Pieces of dock, barges, and other materials that are stored in the water can easily be infested with invasive species. Do not move pieces of dock without first having dried them out completely or decontaminated them.
  • Decontaminate your gear. Use plenty of fresh water, away from saltwater or let your gear dry out completely.
  • Remove colonial tunicates manually from your gear. Dispose of tunicates in a garbage receptacle or let it dry completely. If pressure washing aquatic farm gear cannot be avoided, only do so on land and make sure the outflow does not run back into the sea.
  • Educate a friend about invasive species. Learn about your local marine habitats and the organisms they support. Learn about invasive species (PDF 637 kB) that threaten your local areas and share information with others.